Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752699AbWKBHML (ORCPT ); Thu, 2 Nov 2006 02:12:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752700AbWKBHML (ORCPT ); Thu, 2 Nov 2006 02:12:11 -0500 Received: from amsfep17-int.chello.nl ([213.46.243.15]:58013 "EHLO amsfep16-int.chello.nl") by vger.kernel.org with ESMTP id S1752699AbWKBHMK (ORCPT ); Thu, 2 Nov 2006 02:12:10 -0500 Subject: RE: Can Linux live without DMA zone? From: Peter Zijlstra To: Conke Hu Cc: Jun Sun , linux-kernel@vger.kernel.org, Christoph Lameter In-Reply-To: References: Content-Type: text/plain; charset=UTF-8 Date: Thu, 02 Nov 2006 08:13:11 +0100 Message-Id: <1162451591.27131.2.camel@taijtu> Mime-Version: 1.0 X-Mailer: Evolution 2.6.3 (2.6.3-1.fc5.5) Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2188 Lines: 60 On Thu, 2006-11-02 at 11:43 +0800, Conke Hu wrote: > It seems a good idea. > Is dma zone is still necessay on most modern computers? (don't top post!) if you would have used google, you'd have found this: http://www.mail-archive.com/linux-arch@vger.kernel.org/msg01623.html cheers > -----Original Message----- > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jun Sun > Sent: 2006年11月2日 10:16 > To: linux-kernel@vger.kernel.org > Subject: Can Linux live without DMA zone? > > > I am trying to reserve a block of memory (>16MB) starting from 0 and hide it > from kernel. A consequence is that DMA zone now has size 0. That causes > many drivers to grief (OOMs). > > I see two ways out: > > 1. Modify individual drivers and convince them not to alloc with GFP_DMA. > I have been trying to do this but do not seem to see an end of it. :) > > 2. Simply lie and increase MAX_DMA_ADDRESS to really big (like 1GB) so that > the whole memory region belongs to DMA zone. > > #2 sounds pretty hackish. I am sure something bad will happen > sooner or later (like what?). But so far it appears to be working fine. > > The fundamental question is: Has anybody tried to run Linux without 0 sized > DMA zone before? Am I doing something that nobody has done before (which is > something really hard to believe these days with Linux :P)? > > Cheers. > > Jun > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/